1. Field of the Invention
The present invention relates to a process for treating potassium chloride and more particularly to that for decreasing or taking away bitterness, bad aftertaste and the like undesirable tastes inherent in the potassium chloride.
2. Related Arts
A salting agent is one of important tasting agents to be employed for processing and/or cooking foodstuffs, together with sweetening, souring, seasoning and other agents, and sodium chloride (table salt) is listed as an example of one. In addition to giving a salty taste to various foodstuffs, sodium chloride is important as a preserving agent therefor to prevent putrefaction or molding, and has a close relation with our dietary life in that it is widely employed for preserving fishes and shellfishes in salt as well as for preparing Japanese bean paste (so-called "Miso"), Japanese soy sauces (so-called "Syouyu"), salted and cured vegetables (so-called "Tsukemono"), boiled foods in Japanese soy (so-called "Tsukudani") and the like.
In recent years, however, a relationship between circulatory disorders, so-called "geriatric diseases" such as hyperpiesia, cardiacs or the like, and an excess intake of the sodium chloride has been reported and thus it has been recommended to decrease its intake to cure or prevent the circulatory disorders, kidney diseases, hepatocirrhosis and the like. Therefore, there is a somewhat high tendency to select foodstuffs free from the sodium chloride or containing the same at a lower level, and even healthy persons are concerned. The sodium chloride or the like salting agent, however, complements another agent, for instance, emphasizing the sweetness of a sweetening agent and it can not be avoided that a salty agent-free foodstuff is insipid, showing little or unsufficient taste or flavour. Further, preservation, of course, is reduced if sodium chloride is not used in processing of the foodstuffs.
Therefore, various studies have been made on a salting agent to be substituted for the sodium chloride. An example of a substitute is potassium chloride. The potassium chloride can be obtained from rock-salt (halite), is available commercially at a reasonable price, has no problem with the Food Sanitation Law, has physical properties similar to sodium chloride in molecular weight, crystal structure, solubility and the like, and has effects similar to sodium chloride in preventing against putrefaction and molding, and thus a salting agent, in which a part of sodium chloride is substituted by potassium chloride has been marketed. However, such a marketed salty agent has not widely been employed in the food industry and usual daily diet, since a foreign bitterness and aftertaste will appear, as the mixing ratio of the potassium chloride is increased.
For this purpose, namely for removing such bad taste, various proposals have been made, but each of which intends mainly a masking of the inherent bitterness of potassium chloride, by adding an organic acid such as citric acid, amino acid, a salt thereof, a sweetening agent or a seasoning. For instance, Japanese Unexamined Patent Publication No. 138359/1982 discloses the addition of at least one of glycine, L-alanine, 5'-sodium inosinate, L-sodium glutamate, glycyrrhizin and sodium glycyrrhetinate, and Japanese Unexamined Patent Publication No. 81758/1983 discloses the addition of at least one of sweeteners selected from glycyrrhizin, glycyrrhiza extract, stevioside, monoglucosylstevioside and edible synthetic sweeteners. Further, Japanese Examined Patent Publication No. 13698/1972 discloses a method of preparation of a cooking salt composition, wherein about 20 to 80 weight % of sodium chloride and about 80 to 20 weight % of potassium chloride are mixed to obtain a homogeneous mixture. However, each of such substituting compositions is a mere mixture of powdered raw materials and thus there is a possibility of causing a localization and classification of each component during transportation and use. In addition, there are various problems in the mixing manner and mixing ratio, since homogenous mixing will become difficult when a small amount of the taste improving agent is added to the potassium chloride, and if such agent is added in excess, an inherent taste thereof develops which may impart a bad taste to the foodstuff per se.
Therefore, a study has been tried for not merely masking the bitterness and other undesirable tastes of the potassium chloride but positively suppressing the same to make the taste similar to that of sodium chloride. For instance, Japanese Unexamined Patent Publication No. 198953/1984 discloses a low sodium salting seasoning which comprises a mixture of sodium chloride and potassium chloride in a weight ratio of 1:9 to 1:1 and powdered bittern in 1 to 20 weight % of the seasoning per se. This prior art has a singularity in that a negation of the bitterness of the potassium chloride is intended by adding the powdered bittern which is one of bitter sources. This proposal, however, has disadvantages in that the sodium chloride should be added in at least 10 weight % based on the potassium chloride, and that the use of bittern causes moisture absorption and an acceleration of caking in the potassium chloride, even if the bittern is added in the form of powder.